Cements comprising an aqueous solution of an alkali metal silicate and a polysiloxane which contains hydrocarbonoxy groups



United States Patent CEMENTS COMPRISENG AN AQUEOUS SOLUTION OF AN ALKALIMETAL SILICATE AND A POLY- SILOXANE WHICH CONTAINS HYDROC-AR- BONOXYGROUPS Ronald H. Cooper, Clare County, Mich, assignor to The DowChemical Company, Midland, Mich., a corporation of Delaware No Drawing.Application March 8, 1954, Serial No. 414,896

5 Claims. (Cl. 260-292) This invention relates to improved silicatecements containing certain organosilicon compounds.

Aqueous silicate solutions particularly those of sodium and potassiumsilicates have long been used for acid resistant cements, They have theadvantage of being comparatively durable to aqueous acids and also ofbeing reasonably cheap. However, the term acid resist-ant is a relativeterm and in practice the silicate cements do deteriorate with time whensubjected to aqueous acids such as is often encountered in chemicalprocesses. The problem is further aggravated by the fact that the bestacid resistant cements are obtained by employing cement solution of therange of 38 Baum which have a high ratio of filler to silicate solution.However, these more acid resist-ant compositions are diflicult totrowel. Consequently, the masons employing such cements invariably tendto dilute them with water to give a lower Baum solution or to decreasethe ratio of filler to silicate solution thereby giving a more fluidmix. When either of these two things happens the acid resistance of thecement is substantially lowered.

It is an object of this invention to obviate the above difiiculties byproducing a smooth trowelable silicate cement mix which upon curing hasa high tensile strength, low acid and water absorption, a low lossintensile strength when exposed to acid and water solutions andexcellent vention can be connected through SiOSi linkages. In such casesthe siloxanes would have the general formula where R is a monovalenthydrocarbon radical, R" is as above defined and n and m have the values1 to 1.5 and .03 to 2 respectively. Such compounds are commerciallyavailable and are known in the art as partially hydrolyzedhydrocarbonoxy siloxanes. They are best prepared, for example, bypartially alkoxylating the corresponding halosilanes and thereafteradding suflicient water to the resulting haloalkoxy compound in order tohydrolyze the halogen thereby producing the alkoxylated siloxane.

If desired, the siloxanes employed herein may be those in which amajority of the silicon atoms are linked by SiOSi linkages and theremaining silicon atoms are linked either by SiSi linkages or SiRSilinkages or both. Aliphatic hydrocarbonoxy substituted siloxanescontaining combinations of the above three types of linkages arecommercially available. For example, one which contains all three isprepared by partially alkoxylating the so-called direct process residueby reacting the residue with the desired alcohol. The direct processresidue is obtained by reacting methyl chloride with silicon andthereafter removing methylchlorosilanes boiling below 75 C. atatmospheric pressure. This residue is more fully described in thecopending applications of Arthur J. Barry et al., Serial No. 338,123,filed February 20, 1953, and John W. Gilkey, Serial No. 357,921, filedMay 27, 1953. The partially alkoxylated residue is partially hydrolyzedby adding enough water to remove the chlorine from the silicon. Theresulting product is a complex adherence to brick, ceramics, carbon andgraphite under I both dry and humid conditions. These objectives areaccomplished with the compositions described hereinafter.

This invention relates to an acid resistant cement consistingessentially of a water-glass solution and from 3 to 30% by weight basedon the weight of the alkali metal silicate in the water-glass solution,of an aliphatic hydrocarbonoxy substituted siloxane in which at least amajor portion of the silicon atoms are connected by SiOSi linkages andany remaining linkages are of the type SiSi and/ or SiR'Si where R is adivalent hydrocarbon radical. The remaining valences of the siliconatoms in the siloxane are satisfied with monovalent hydrocarbon radicalsin the amount of on the average from 1 to 1.5 said radicals per siliconatom and radicals of the formula OR" in which R" is an aliphatichydrocarbon radical. The latter radicals are present in the amount of onthe average from .03 to 2 OR" radicals per silicon atom. In the siloxanethe sum of the average number of hydrocarbon radicals and the OR"radicals is not greater than 3.

"Organosilicon compounds which are operative in this invention arealiphatic hydrocarbonoxy substituted siloxanes. It has been found thatthis type of siloxane is particularly adaptable for use in connectionwith silicate cements. Quite surprisingly the alkali metal salts of thecorresponding siloxanes show no substantial improvement over silicatecement containing no organosilicon compound. For the purpose of thisinvention all of the silicon atoms in the hydrocarbonoxy siloxanes ofthis inmaterial containing silicon bonded alkoxy groups.

Although the use of completely hydrolyzed siloxanes alone is not withinthe scope of this invention nevertheless a minor amount of suchsiloxanes can be mixed with the alkoxysiloxanes and the mixtureincorporated in silicate cements. The term completely hydrolyzedsiloxanes means siloxanes whichcontain no substantial amount ofhydrolyzable groups such as hydrocarbonoxy groups. The term minor amountmeans that the completely hydrolyzed siloxane is present in amount lessthan 50% by weight of the total weight of the organosiloxanecomposition. Completely hydrolyzed siloxanes have the unit formula whereR is as above defined and x has an average value of from 1 to 2.

For the purpose of this invention the R groups attached to the siliconcan be any monovalent hydrocarbon radical such as for example methyl,ethyl, octadecyl, vinyl, allyl, cyclohexyl, cyclopentyl, cyclohexenyl,tolyl, benzyl, phenyl, xenyl and naphthyl, R can be any divalenthydrocarbon radical such as methylene, ethylene, butylene, phenylene andxenylene. R" can be any aliphatic hydrocarbon radical such as methyl,ethyl, propyl, isopropyl, butyl, octadecyl, vinyl, allyl and cyclohexyl.Preferably R" should contain less than 6 carbon atoms.

The silicates employed in this invention are aqueous solutions of sodiumand potassium silicates commercially known as water-glass. For thepurpose of this invention the concentration of these solutions can bevaried 'to give the desired consistency and setting time. Typicalconcentrations which are normally present in commercial silicatesolutions are those in which the specific gravity of the solution rangesfrom 1.325 to 1.355. Normally the ratio by weight of alkali metal oxideto SiOz will be of the order of 1:3 to 1:35. It should be understoodthat the above ranges are merely exemplatory and that 3 h omposi ions. ohis i vention. ar i no. ay limit d thereto.

The amount of organosilicon compound relative to the amount of silicatein; the cement can be varied from 3 to 30% based on the weight of thealkali metal silicate in the water-glass solution. In general,particularly when fillers are employed in the cement, the amount oforganosilicon compound will range from .5 to 3% of the over" allcomposition (i. e., water-glass solution plus filler plusorganosiloxane).

If desired, fillers may be employed in the cements of this invention.Suitable fillers are siliceous materials such as silex, diatomaceousearth, sand and the like. The amount of filler employed will depend uponthe consistency desired in the cement mix. In general, the amount offiller will vary from 50 to 75% of the total weight of the cement.

The compositions of this invention are particularly useful for cementingmaterials in contact with aqueous acids.

The following examples are illustrative only and should SiQz, 1.42%aluminum oxide, 4% sodium fluorosilicate, 2.91% volatiles and theremainder being traces of iron, calcium and magnesium oxides.

In preparation of the cement the organosiloxane was added to the sodiumsilicate solution with continuous stirring until a homogenous dispersionwas obtained. The filler was then gradually added with stirring until asmooth mix was formed. The resulting mix was poured into a figure Sbriquette mold and allowed to harden for at least 24 hours beforeremoving therefrom. The briquettes were then aged under the conditionsshown in the table below and the properties thereof determined as shown.

In the table runs 1 to 12 pertain to compositions within the scope ofthis invention, 13 gives average values for a total of 1G cementsprepared with the same waterglass and filler but omitting the siloxane,run 14 shows the average values obtained from 7 runs employing the samesilicate solution and filler but using a sodium salt of siloxane A whichcontained about 1.1 sodium atoms per silicon and no methoxy groups.

Composition of cement in After days in 20% H01 After 30 days indistilled water percent by Wt. based on Tensile at 110 C. at 100 0.total composition 1 strength in p. s. i. after 30 Na days air PercentTensile Percent Tensile Filler silicate Siloxanc drying w in Penetrationwt. in Penetration solution gain p. s. i. gain p. s. i.

70. 70 28. 30 90 500 10. 79 450 Partial. 6. 38 438 Partial. 70. 70 27.10 2. 00 445 15.10 8. 30 493 D0. 70.00 27. 00 2. 477 13.00 68. 85 29. 1590 480 9. 90 6. 10 425 Partial 69. 20 28. 80 1.80 360 11.20 3. 68 528D0. 490 14. 30 9. 54 385 Do. 590 10. 34 3. 30 507 D0; 538 9. 56 5. 67380 Do. 452 13. 50 3. 70 370 D0. 385 9. 69 6. 70 395 D0. 505 13.35 8. 54410 Do. 493 10. 90 7. 36 450 Do. Average 535 11. so 5. 8 435 13 303 18.415. 5 335 Complete. 14 300 18.6 15. 5 271 Varied.

1 The difference between the total percentages and 100% represents theamount of toluene in the siloxane.

not be construed as limiting the invention which is properly delineatedin the appended claims.

Example 1 The siloxane employed in the experiments of this example was amixture of (A) 85% by weight of a fluid alkoxylated polysiloxane and (B)15% by weight of a nonalkoxylated polysiloxane resin. Siloxane A had anaverage of about 1.1 total monovalent hydrocarbon radicals per siliconatom (said radicals being methyl, ethyl, propyl, and butyl) and 24% byweight silicon bonded methoxy groups. A major proportion of the iliconatoms in this siloxane were linked through SiOSi linkages and a minorproportion of the silicon atoms. were linked through SiSi linkages andSiRSi linkages in which R was methylene or ethylene. This siloxane wasprepared from the direct process residue by the method described supra.

Siloxane B was a copolymer composed of SiOz and MesSiOs units in whichthere was an average of about 1.2 methyl groups per silicon atom. Thissiloxane was benzene soluble and all of the polymer linkages thereinwere SiOSi linkages.

The water-glass employed in this invention was an aqueous solution ofsodium silicate having a specific gravity of about 1.355 or 38 Baum. Thesodium silicate was composed of about one part by weight NazO to 3.20parts by weight SiOz. This sodium silicate was diluted to give asolution having aspecilic gravity of 1.353 which contains about 37% byweight solids, i. e., Na20+SiOz.

The filler employed was a powdered following composition in per cent byweight:

silica having the 92.4

Example 2 Equivalent results are obtained when a siloxane having thecomposition 67 mol per cent phenylmethylsiloxane and 33 mol per centmonophenylsiloxane and containing 20% by weight silicon bondedisopropoxy groups, is employed in the procedure of Example 1.

Example 3 Equivalent results are obtained when an aqueous solution ofpotassium silicate having a composition equivalent to the silicatesolution of Example 1, is employed in the process of that example.

That which is claimed is:

1. An acid resistant cement consisting essentially of an aqueouswater-glass solution and from 3 to 30% by weight based on the weight ofthe alkali metal silicate in the water-glass solution of an aliphatichydrocarbonoxy substituted siloxane in which at least a major portion ofthe silicon atoms are connected by SiOSi linkages and any remaininglinkages are selected from the group consisting of SiSi and SiRSilinkages where R is a divalent hydrocarbon radical, the remainingvalences of the silicon atoms in said siloxane being satisfied bymonovalent hydrocarbon radicals in the amount of on the average from 1to 1.5 said radicals per silicon atom and radicals oi the formula OR" inwhich R" is an aliphatic hydrocarbon radical, in amount of on theaverage from .03 to 2, OR" radicals per silicon atom.

2. An acid resistant cement consisting essentially of an aqueouswater-glass solution, a filler and from 3 to 30% by. weight based on theweight of the alkali metal silicate in the water-glass solution of analiphatic hydrocarbonoxy substituted siloxane in which at least a majorportion of the silicon atoms are connected by SiOSi linkages and anyremaining linkages are selected from the group consisting of SiSi andSiR'Si linkages where R is a divalent hydrocarbon radical, the remainingvalences of the silicon atoms in said siloxane being satisfied withmonovalent hydrocarbon radicals in the amount of on the average from 1to 1.5 said radicals per silicon atom and radicals of the formula OR" inwhich R" is an ali-- phatic hydrocarbon radical, in amount of on theaverage from .03 to 2 OR" radicals per silicon atom.

3. An acid resistant cement consisting essentially of an aqueouswater-glass solution, a filler andlfrom 3 to 30% by weight based on theweight of the alkali metal silicate in the water-glass solution of asiloxane composed of a mixture of (A) an aliphatic hydrocarbonoxysubstituted siloxane in which at least a major portion of the siliconatoms are connected by SiOSi linkages, any remaining linkages beingselected from the group consisting of SiSi and SiR'Si where R is adivalent hydrocarbon radical, the remaining valences of the siliconatoms in siloxane A being satisfied with monovalent hydrocarbon radicalsin amount of on the average from 1 to 1.5 said radicals per silicon atomand radicals of the formula OR in which R" is an aliphatic hydrocarbonradical, in amount of on the average from .03 to 2 OR" radicals persilicon atom and (B) less than 50% by weight based on the total weightof the siloxanes of a siloxane of the formula R,SiO T where R is amonovalent hydrocarbon radical and x has an average value of from 1 to2.

4. An acid resistant cement comprising an aqueous sodium silicatesolution, a filler and from 3 to 30% by weight based on the weight ofthe sodium silicate in the aqueous solution of a siloxane in which atleast a major portion of the silicon atoms are connected by SiOSilinkages and any remaining linkages are selected from the groupconsisting of SiSi and SiR'Si where R is selected from the groupconsisting of methylene and ethylene radicals, the remaining valences ofthe silicon atoms in the siloxane being satisfied by radicals selectedfrom the group consisting of alkyl and phenyl radicals in the amount ofon the average froml to 1.5 said radicals per silicon atom and alkoxyradicals containing less than 6 carbon atoms in the amount of from .03to 2 alkoxy radicals per silicon atom.

5. An acid resistant cement consisting essentially of an aqueous sodiumsilicate solution, a filler and from 3 to 30% by weight based on theweight of the sodium silicate in the aqueous solution of a siloxanecomposed of a mixture of (A) a siloxane in which a major proportion ofthe silicon atoms are connected by SiOSi linkages, the remaininglinkages being SiSi and SiR'Si linkages where R is selected from thegroup consisting of methylene and ethylene radicals, the remainingvalences of the silicon atoms in siloxane A being satisfied withmonovalent hydrocarbon radicals selected from the group consisting ofmethyl, ethyl, propyl and butyl radicals, said radicals being present inthe amount of on the average from 1 to 1.5 radicals per silicon atom,and alkoxy radicals containing less than 6 carbon atoms in amount of onthe average from .03 to 2 alkoxy radicals per silicon atom and (B) lessthan by weight based on the weight of the total siloxane mixture of asiloxane of the formula (CHa)aSiO4 a.- in which x has an average valueof from 1 to 2 inclusive.

References Cited in the file of this patent UNITED STATES PATENTS2,588,828 Greiner Mar. 11, 1952

1. AN ACID RESISTANT CEMENT CONSISTING ESSENTIALLY OF AN AQUEOUSWATER-GLASS SOLUTION AND FROM 3 TO 30% BY WEIGHT BASED ON THE WEIGHT OFTHE ALKALI METAL SILICATE IN THE WATER-GLASS SOLUTION OF AN ALIPHATICHYDROCARBONOXY SUBSTITUTED SILOXANE IN WHICH AT LEAST A MAJOR PORTION OFTHE SILICON ATOMS ARE CONNECTED BY SIOSI LINKAGES AND ANY REMAININGLINKAGES ARE SELECTED FROM THE GROUP CONSISTING OF SISI AND SIR''SILINKAGES WHERE R'' IS A DIVALENT HYDROCARBON RADICAL, THE REMAININGVALENCES OF THE SILICON ATOMS IN SAID SILOXANE BEING SATISFIED BYMONOVALENT HYDROCARBON RADICALS IN THE AMOUNT OF ON THE AVERAGE FROM 1TO 1.5 SAID RADICALS PER SILICON ATOM AND RADICALS OF THE FORMULA OR" INWHICH R" IS AN ALIPHATIC HYDROCARBON RADICAL, IN AMOUNT OF ON THEAVERAGE FROM .03 TO 2 OR" RADICALS PER SILICON ATOM.